The present invention relates to a wire matrix printer head, and more specifically to an inking apparatus which directly supplies liquid ink to a group of print wires.
In a wire matrix printer without requiring an ink ribbon, a group of print wires are guided so as to pass through holes formed in an ink reservoir by which inking is achieved. Ink passes from a tank to a capillary path or a tube and is supplied to the reservoir. The wire printer of the type as described has been known in U.S. Pat. Nos. 4,194,846, 4,279,519 and 4,353,654. U.S. Pat. No. 4,445,127 is also known which discloses the type wherein, instead of provision of an ink reservoir, an ink applicator such as a felt projected from an ink container is brought into direct contact with a group of print wires. In the wire printer using the ink reservoir or ink applicator, the group of print wires are subjected to inking by relatively intensive pressure contact between the print wire and the ink reservoir or the ink applicator. However, as a friction of high level occurs therebetween, the ink reservoir or the ink applicator around the print wires is deteriorated or worn out, failing to insure sufficient inking for a long period of time.
On the other hand, there has been proposed U.S. Pat. No. 4,456,393 disclosing the type in which a group of print wires are guided so as to pass through an ink chamber filled with ink, without using an ink reservoir or an ink applicator. However, in the wire printer of the type as described, a pump device has to be provided to supply pressurized ink to the ink chamber so as to forcibly lubricate the group of print wires.